Monument Creek hydraulics project

Eric Leonard

Colorado College

Undergraduate course in geomorphology with an Introductory Geo prerequisite and intro physics recommended. About 1/3 of the students have taken only Introductory Geology, a third have taken Introductory Geology, Mineralogy and Introduction to Petrology, and a third have taken each of these these and several other geology classes.

Students need to have read and tried to understand the basics of fluvial hydrology and sediment transport covered in an Introductory-level geomorphology textbook.

This is a project that is done as a stand-alone exercise that is given about midway through the course. It is sometime the only fluvial geomorphology project in the course. Other years it is coupled with a project on alluvial stratigraphy and arroyo formation.

Primary content goal; to allow students to develop a familiarity with stream hydraulics, paleohydraulics, and frequency magnitude analysis (in this case flood frequency) through hands-on application of book concepts.

Primary higher-order thinking skills goals: developing an ability to design a sampling/measurement methodology to answer specific questions posed in the assignment (the amount of faculty direction towards this project design can be varied depending on the background of the class).

Other skills goals: to gain familiarity with use of some field survey instrumentation, with the USGS Water site, with flood-frequency analysis methods, and with us of some statistical applications in EXCEL. Also to develop skills in working in groups and in communicating procedures used and results obtained by one group to another group.

Students are given some general questions (file "IntroQuestions_07.pdf") related to project design during the class session before the main project is handed out. They need to use their textbook and/or other class resources to attempt to answer these questions and to prepare to discuss them the next class session. These questions concern field reconstruction of flood hydraulics, specifically. of bankfull flow. At this next class session we discuss their answers to the preliminary questions. Students are then given the main project handout (Monument_Ck_Problem_07.pdf). This gives them the general questions to be answered in the project. After reading it, students brainstorm again as a class about how to go about answering the questions.

Students then divide themselves into research of three. These teams will synthesize data together and ultimately write up the project together. Each team then sends one member to join members of other teams to do one of the three main aspects of the field or computer work (1) field identification of the bankfull channel and measurement of bankfull channel geometry, (2) field determination of modern channel roughness from modern stream hydraulics (Manning's n is back-calculated from present channel geometry and flow), (3) development of a flood-frequency curve for this reach of Monument Creek from USGS discharge data. These working groups (with one member from each research team) work initially independently in the field and subsequently doing calculations in the lab, or on the computer. Once each working group has completed what it can do on its own, these groups split up and each member of each group carries the groups results back to his/her research team, and explains to the other members of the research team what he/she has done to this point and what results he/she has for the team. The team then works to synthesize he results into an overall answer to the questions posed at the beginning of the lab (confusing enough for you?). Each research team then writes up the results, sometimes (as in 2007) as a lab write up, in other years in scientific paper format. Whether the project is turned in simply as a lab write up or as a scientific paper, students are always asked to assess sources of error and how they might affect the results.

Key words: Fluvial geomorphology, fluvial hydraulics, bankfull discharge, flood-frequency analysis Designed for a geomorphology course

I evaluate whether students have met the goals of the project in my assessment of their group project write-ups.

For flood-frequency data:
http://water.usgs.gov/

If you do not want to have students try to back calculate a Manning's n for the modern stream a good source for estimating Manning's n is:

USGS Water Supply Paper 1849, by H.H. Barnes, Jr. (http://wwwrcamnl.wr.usgs.gov/sws/fieldmethods/Indirects/nvalues/index.htm)